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mechanical-force
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Singularity reduction of a 3-UPS mechanism with 6 DOF for haptic applications
, Article ASME 2010 10th Biennial Conference on Engineering Systems Design and Analysis, ESDA2010, 12 July 2010 through 14 July 2010 ; Volume 3 , 2010 , Pages 619-626 ; 9780791849170 (ISBN) ; Khodabakhsh, M ; ASME Turkey Section ; Sharif University of Technology
Abstract
A method for singularity reduction in a triangular 3-UPS mechanism is discussed. This mechanism usually has singularity near the origin. Changing the active joint angle can arrive at a suitable workspace near the origin without any singularity. Moreover, a 4-UPS mechanism, based on adding one additional leg to the 3-UPS mechanism, has a larger singular free workspace. Moreover, force analysis of two different mechanisms shows a reasonable and consistent force distribution between the different actuators. Singular free workspace is one of the characteristics which makes this mechanism ideal for haptic applications
proposal for tunable dual channel transmitter and mechano-optical switch based on photonic crystal
, Article Applied Optics ; Volume 51, Issue 32 , 2012 , Pages 7784-7787 ; 00036935 (ISSN) ; Noshad, M ; Sharif University of Technology
OSA - The Optical Society
2012
Abstract
In this article we propose a novel mechano-optical switch and dual channel transmitter based on photonic crystal. The device consists of two waveguides and an elliptical cavity in a square lattice structure. Two optical signals at separate wavelengths are inserted in the input waveguide. The elliptical cavity can be rotated using a mechanical force, which results in the control of transmission efficiency at each of the wavelengths. In addition, rotation of the cavity can be considered as a switching action, which changes on-off states of the output signals
Investigation of Activation Mechanism of Mechanosensitive Nano Ion Channels
, Ph.D. Dissertation Sharif University of Technology ; Vosoughi, Manochehr (Supervisor) ; Jamali, Yusef (Supervisor) ; Naghdabadi, Reza (Supervisor)
Abstract
Mechanosensitive (MS) channels are ubiquitous molecular force sensors that respond to a number of different mechanical stimuli including tensile, compressive and shear stress. One of the main mechanisms to functionally study these channels is the patch clamp technique. Here we use continuum mechanics to probe the question of how curvature, in a standard patch clamp experiment, at different length scales (global and local) affects a model MS channel. Firstly, to increase the accuracy of the Laplace’s equation in tension estimation in a patch membrane and to be able to more precisely describe the transient phenomena happening during patch clamping, we propose a modified Laplace’s equation. In...
Mechanical force optimization on superconductor element of shield-type superconducting FCLs
, Article 2012 3rd Power Electronics and Drive Systems Technology, PEDSTC 2012, 15 February 2012 through 16 February 2012 ; February , 2012 , Pages 495-499 ; 9781467301114 (ISBN) ; Vakilian, M ; Fardmanesh, M ; Sharif University of Technology
2012
Abstract
Superconducting fault current limiter (SFCL) is classified in the category of most efficient fault current limiters. Inductive shield-type SFCLs use bulk superconductor rings in their structure. At the fault occurrence, the induced current in the superconductor ring causes high mechanical forces on the ring. In the preliminary fabricated prototypes of this work, this mechanical force caused several damages to the superconductor element. Thus in this paper an analytical method is introduced to yield the main design parameters of the shield-type SFCL to ensure the sufficient mechanical withstand capability of the superconductor ring employed in this design. A prototype SFCL of this type is...
Bidirectional water transport through non-straight carbon nanotubes
, Article Journal of Molecular Liquids ; Volume 276 , 2019 , Pages 39-46 ; 01677322 (ISSN) ; Moosavi, A ; Sharif University of Technology
Elsevier B.V
2019
Abstract
Natural nanochannels and those used for applied purposes are often several nanometers in diameter and have lengths up to micrometer scales. Since normally no pressure gradient, mechanical force or electrical field is exerted on fluids in these situations, the fluid flow within them is not single-file and can be bidirectional. For this reason, studying the behavior of bidirectional flows in the channels is of paramount importance. In this study, a comprehensive investigation on the straight and non-straight bidirectional water transfer through carbon nanotubes is conducted via extensive molecular dynamics simulations. The results indicate that by changing the length, the diameter and the...
Constitutive Modeling of Nonlinear Tumor Growth; A Finite Element Approach
,
M.Sc. Thesis
Sharif University of Technology
;
Naghdabadi, Reza
(Supervisor)
Abstract
Mechanical forces play a crucial role in tumor patho-physiology. Compression of cancer cells inhibits their proliferation rate and induces apoptosis. Additionally, compression of intratumor blood vessels has negative impacts on drug delivery system. Despite the great importance of the mechanical forces on the pathology of cancer, there are limited studies on the constitutive modeling of tumors. In this study, first, the tumor growth inside a rigid cylinder with an exponential growth function is represented, a model mimicking the growth of ductal carcinoma. Then, a mathematical model of a spherical tumor growth with a Gompertz growth function is represented. Using the notion of multiple...
Force-displacement model for solid confined masonry walls with shear-dominated failure mode
, Article Earthquake Engineering and Structural Dynamics ; Volume 46, Issue 13 , 2017 , Pages 2209-2234 ; 00988847 (ISSN) ; Bakhshi, A ; Ghannad, M. A ; Sharif University of Technology
Abstract
This paper addresses the behavior of confined masonry walls with dominating shear failure mode in walls. For this purpose, failure modes of these walls are classified in details. For each failure mode, complete set of analytical-based relations for deriving parameters related to backbone curves is introduced. Calibrated finite element analyses are utilized as a benchmark for verification of some of the assumptions. The results of the proposed relations are compared with those of several Iranian and non-Iranian experimental data. Sensitivity analysis is performed in order to understand the effects of important behavioral characteristics of these walls. The results of this study indicate that...
PH-Sensitive stimulus-responsive nanocarriers for targeted delivery of therapeutic agents
, Article Wiley Interdisciplinary Reviews: Nanomedicine and Nanobiotechnology ; Volume 8, Issue 5 , 2016 , Pages 696-716 ; 19395116 (ISSN) ; Eslami, M ; Sahandi Zangabad, P ; Mirab, F ; Farajisafiloo, N ; Shafaei, Z ; Ghosh, D ; Bozorgomid, M ; Dashkhaneh, F ; Hamblin, M. R ; Sharif University of Technology
Wiley-Blackwell
2016
Abstract
In recent years miscellaneous smart micro/nanosystems that respond to various exogenous/endogenous stimuli including temperature, magnetic/electric field, mechanical force, ultrasound/light irradiation, redox potentials, and biomolecule concentration have been developed for targeted delivery and release of encapsulated therapeutic agents such as drugs, genes, proteins, and metal ions specifically at their required site of action. Owing to physiological differences between malignant and normal cells, or between tumors and normal tissues, pH-sensitive nanosystems represent promising smart delivery vehicles for transport and delivery of anticancer agents. Furthermore, pH-sensitive systems...